Sudan Academy of Sciences (SAS)

Measurement of Dose Received in Knee Joint X-ray Examination

By: Basamat Musa Hajo Abbashar

2014

بسم الله الرحمن الرحيم

Sudan Academy of Sciences (SAS) Atomic Energy Council

Measurement of Dose Received in Knee Joint X-ray Examination

B.Sc. lap Physics Sudan University of Science and Technology (2009)

A Dissertation submitted to Sudan Academy of Science in Partial fulfillment of

The Requirements of Master of Sciences in Medical Physics (2014)

Supervisor:

Dr. Yousif Mohamed Yousif Abdallah Sudan University of Sciences and Technology

2014

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Dedication I dedicate my dissertation research to my family and friends. Special feeling of gratitude to my loving parents, whose words of encouragement and push for tenacity ring in my ears, and very special to my sisters who they never left my side. Also I dedicate this dissertation to my friends. I will always appreciate all they have done to me.

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Acknowledgement: A special thanks Dr. Yousif Mohamed Yousif Abdallah; my supervisor for his countless hours of reflecting,reading,encouraging , and most of all patients throughout the entire process . I would like to acknowledge and thank my colleagues in the Sudan Academy of sciences for allowing me to conduct my research and providing my assistance requested . Special thanks go to the members of Medical Physics Department staff for their continued support. Finally I would like to thank my teachers, doctors in my loved country, especially in the physics Department for any advance that support me to complete my higher study.

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Abstract: Diagnostic X-ray examinations play an important role in the health care of the population. These examinations may involve significant irradiation of the patient and probably represent the largest man-made source of radiation exposure for the population. This study was performed in Khartoum teaching hospital in period of January to June 2014. This study performed to assess the effective dose (ED) received in knee joint radiographic examination and to analyze effective dose distributions among radiological departments under study. The study was performed in Khartoum teaching hospital, covering two x-ray units and a sample of 50 patients. The following parameters were recorded age, weight, height, body mass index (BMI) derived from weight (kg) and (height (m)) and exposure factors. The dose was measured for knee joint x-rays examination. For effective dose calculation, the entrance surface dose (ESD) values were estimated from the x-ray tube output parameters for knee joint AP and lateral examinations. The ED values were then calculated from the obtained ESD values using IAEA calculation methods. Effective doses were then calculated from energy imparted using ED conversion factors proposed by IAEA. The results of ED values calculated showed that patient exposure were within the normal range of exposure. The mean ED values calculated were ( 2.49 +_0.03) and (5.60 +_ 0.22) mili Grey for knee joint AP and lateral examinations, respectively. Further studies are recommended with more number of patients and using more two modalities for comparison.

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الملخص:تلعب الاشعه السينيه دورآ ھامآ في الرعايه الصحيه للسكان قد لاتنطوي ھذه الفحوصات على تعرض

قدمت قياس الاشعه السينيه من .المرضى لمقدار كبير من الاشعه وربما تمثل اكبر مصدر تعرض للسكان ؤينه المنتجه يوفر تقييم قياس الاشعه الم.المؤينه التي يتم انتاجھا تقييم مفيد من اجمالي الطاقه الممتصه

اجمالي الطاقه الممتصه اجريت ھذه الدراسه في مستشفى الخرطوم التعليمي في الفتره من يناير الى يونيو اجريت ھذه الدراسه لتقييم الجرعه الفعاله في حالة تصوير مفصل الركبه وتحليل وتوزيع الجرعات 2014

في مستشفى الخرطوم التعليمي لتشمل الدراسه وحدتين من الفعاله في اقسام الشعه قيد الدراسه اجريت مريض سجلت المعلومات الاتيه؛العمر والوزن و الطول ومؤشر كتلة 50وحدات الاشعه السينيه وعينه من

وعوامل التعريض تم قياس الجرعه في حالة مفصل الركبه ) م(والطول ) كجم(الجسم المستمد من الوزنجرعة مدخل السطح من قيم مخرجات انبوب الشعه السينيه في حالة تصوير لحساب الجرعه الفعاله قدرت

مفصل الركبه الامامي والجانبي ومن ثم تم حساب الجرعه الفعاله من القيم المتحصل عليھا من جرعة مدخل السطح باستحدام طريقة حساب الوكاله العالميه للطاقه الذريه ومن ثم حساب الجرعه الفعاله من

منقوله بواسطه الجرعه الفعاله باستحدام عوامل التحويل القترحه عن طريق الوكالھالعالميه للطاقه الطاقه الملي )0.03_+2.49(الذريه كان متوسط القيم المحسوبه في حالة تصوير مفصل الركبه الامامي يساوي

لآلا ملي غري ينصح بالمزيد من مثل ھذه الدراسات مستقب)0.22_+5.60(غري والجانبي يساوي . .وباستحدام اكثر من طريق للتصوير بالاشعه السينيه للمقارنه

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Table of Contents: Dedication .............................................................................................................. i Acknowledgment ...................................................................................................ii Abstract................................................................................................................ .iii Abstract (Arabic) ................................................................................................. .iv List of Contents....................................................................................................... v List of Figures ........................................................................................................vi List of Tables ....................................................................................................... vii Chapter one: Introduction and Literature Review 1.1. Introduction ..................................................................................................... 1 1.2. Problem of the study ....................................................................................... 3 1.3. Objectives ....................................................................................................... 4 1.3.Specific objectives.....................................................................................,...... 4 1.4. The anatomy of knee joint .............................................................,…............ 5 1.5. Dose Measurement in Conventional x-rays ...................................................11 1.6. Effective dose…..............................................................................................12 1.7. Measurement Dose in knee joint .................................................................. 14 1.8. The Radiographic technique of knee joint imaging ......................................15 1.9. The Radiographic technique of knee joint imaging ........................,….,.......19 1.10. The estimate skin dose for Knee Joint Radiography ................................. 21 1.11. Entrance Surface Dose (ESD) .................................................................... 25 Chapter two: Materials and Methods…………………………………………..27 2.1. Materials ....................................................................................................... 27 2.1.1.Equipments ................................................................................................. 27 2.1.2. Patients ....................................................................................................... 27 2.2. Methods ......................................................................................................... 27 2.2.1.Study duration ................................................................................,,........... 27 2.2.2.Study place ....................................................................................,..,,........ 27 2.2.3.Method of data collection ....................................................................,...... 28 2.2.4.Method of data analysis ......................................................................,....... 29 2.2.5.Method of data storage ................................................................................ 29 3.5.3. Ethical issue................................................................................................ 29 Chapter three: Results and Discussion……………………………………..…30 3.1 Results ………………………………...……………………………….....…30 3.2 Discussion...................................................................................................... 36 Chapter four :Conclusion Recommendations and References ……………....38 4.1 Conclusion..................................................................................................... 38 4.2 Recommendations…………………………………………………………..40 4.3References ...................................................................................................... 41

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List of Figures: Figure 1-1. the bones of the knee joint; A; Anterior view B; Posterior view ..…..6 Figure 1-2. articulation of Knee joint …………………………………..…….....7 Figure 1-3. Tendons of Knee joint ……………………………………….......….9 Figure 1-4. knee joint muscles ……………………………………………….…10 Figure 1-5. Antero-posterior weight bearing radiographs of a patient with joint space…………………………………………………………………….……….17 Figure 1-6. Position of patient for tunnel view of knee: the knee is flexed 40-50 degree With cassette under flexed knee the x-ray is angulated in same degree b from below to obtain view of inter condoyle notch. ………………………..…..20 Figure 1-7. ion chamber on dose product meter which attached to diaphragm housing …………………………………………………….…………………….24 Figure 3-1. Correlation between entrance skin dose ESD (mGy) and body mass index BMI (Kg/m) of patients undergoing Knee joint X-ray……………………32 Figure 3-2: correlation between entrance skin dose ESD (mGy) and weight (mass) of the body (Kg) of patients undergoing knee joint X-ray……………....34 Figure 3-3: correlation between entrance skin dose ESD (mGy) and tube potential kVp to patients undergoing lateral knee joint X-ray …………………………….35

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List of Tables: Table 1-1. The evolving tissue weighting ……………………..………………13 Table 2.1. X-rays equipments specifications……………………..…………....27 Table 3-1 The age distribution for both gender among the study sample…………………………………………………………………………...31 Table 3-2. The mean and standard deviation of Body mass index distribution For both gender among the study sample………………….…………………..…….32 Table 3-3. The mean and standard deviation of exposure factors used for Knee Joint Examination in the study sample…………………..……….……….…....33 Table 3.4. Exposure factors, number of films and dose values for Knee Joint Examination……………………………………………………………………..34

 

 

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Chapter One

Introduction and Literature Review

1.1. Introduction: Radiography started in 1895 with the discovery of X-rays (later also called Röntgen rays

after the man who first described their properties in rigorous detail),a type of

electromagnetic radiation. Soon these found various Applications, from helping to find

shoes that fit, to the more lasting Medical uses. X-rays were put to diagnostic use very

early, before the dangers of ionizing radiation were discovered.Initially, many groups of

staff conducted radiography in hospitals, including physicists, photographers,

doctors,nurses, and engineers. The medical specialty of radiology grew up around the

new technology, and this lasted many years. When new diagnostic tests involving X-rays

were developed, it was natural for the radiographers to be trained and adopt this new

technology. This happened first with fluoroscopy, computed tomography (1960s), and

mammography. Ultrasound(1970s) and magnetic resonance imaging (1980s) was added

to the list of skill,s ued by radiographers because they are also medical imaging, but these

disciplines do not use ionizing radiation or X-rays. Although a non specialist dictionary

might define radiography quite narrowly as "taking X-ray images", this has only been

part of the work of an "X-ray department", radiographers, and radiologists for very long

time. X-rays are also exploited by industrial radiographers in the field of nondestructive

testing, where the newer technology of ultrasound is also used.diagnostic radiography

involves the use of both ionizing radiation and non ionizing radiation to create images for

medical diagnosis (Wall and Hart, 2003).The predominant test and the actual film or

digital image). X-rays are the second most commonly used medical tests, after laboratory

tests. This application is known as diagnostic radiography. Since the body is made up of

various substances with differing densities, X-rays can be used to reveal the internal

structure of the body predominant test is still the X-ray (the word X-ray is often used for

both on film by highlighting these differences using attenuation, or the absorption of X-

 

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ray photons by the denser substances (like calcium-rich bones). Medical diagnostic

radiography is undertaken by a specially trained professional called a diagnostic

radiographer in the UK, or a radiologic technologist in the USA. The creation of images

by exposing an object to X-rays or other high-energy forms of electromagnetic radiation

and capturing the resulting remnant beam (or "shadow") as a latent image is known as

"projection radiography." The "shadow" may be converted to light using a fluorescent

screen, which is then captured on photographic film, it may be captured by a phosphor

screen to be "read" later by a laser (CR), or it may directly activate a matrix of solid-state

detectors (DR similar to a very large version of a CCD in a digital camera). Bone and

some organs (such as lungs) especially lend themselves to projection radiography. It is a

relatively low-cost investigation with a high diagnostic yield. Projection radiography uses

X-rays in different amounts and strengths depending on what body part is being imaged.

Hard tissues such as bone require a relatively high energy photon source, and typically a

tungsten anode is used with a high voltage (50-150 kVp) on a 3-phase or high-frequency

machine to generate braking radiation. Bony tissue and metals are denser than the

surrounding tissue, and thus by absorbing more of the X-ray photons they prevent the

film from getting exposed as much. Wherever dense tissue absorbs or stops the X-rays,

the resulting X-ray film is unexposed, and appears translucent blue, whereas the black

parts of the film represent lower-density tissues such as fat, skin, and internal organs,

which could not stop the X-rays. This is usually used to see bony fractures, foreign

objects (such as ingested coins), and used for finding bony pathology such as

osteoarthritis, infection (osteomyelitis), cancer (osteosarcoma),as well as growth studies

(leg length, achondroplasia, scoliosis, etc.) (Wall and Hart, 2003). Soft tissues are seen

with the same machine as for hard tissues, but a "softer" or less-penetrating X-ray beam

is used. Tissues commonly imaged include the lungs and heart shadow in a chest X-ray,

the air pattern of the bowel in abdominal X-rays, the soft tissues of the neck, the orbits by

a skull X-ray before an MRI to check for radiopaque foreign bodies (especially metal),

and of course the soft tissue shadows in X-rays of bony injuries are looked at by the

radiologist for signs of hidden trauma (for example, the famous "fat pad" sign on a

fractured elbow). Dental radiography uses a small radiation dose with high penetration to

view teeth, which are relatively dense. A dentist may examine a painful tooth and gum

 

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using X-ray equipment. The machines used are typically single-phase pulsating DC, the

oldest and simplest sort. Dental technicians or the dentist may run these machines

radiologic technologists are not required by law to be present. Mammography is an X-ray

examination of breasts and other soft tissues. This has been used mostly on women to

screen for breast cancer, but is also used to view male breasts, and used in conjunction

with a radiologist or a surgeon to localize suspicious tissues before a biopsy or a

lumpectomy. Breast implants designed to enlarge the breasts reduce the viewing ability

of mammography, and require more time for imaging as more views need to be taken.

This is because the material used in the implant is very dense compared to breast tissue,

and looks white (clear) on the film. The radiation used for mammography tends to be

softer (has a lower photon energy) than that used for the harder tissues. Often a tube with

molybdenum anode is used with about 30, 000 volts (30 kV), giving a range of X-ray

energies of about 15-30 keV. Many of these photons are "characteristic radiation" of a

specific energy determined by the atomic structure of the target material (Mo-K

radiation) (Shrimp ton et al, 2003).

1.2. Problem: The knee joint joins the thigh with the leg and consists of two articulations: one between

the femur and tibia, and one between the femur and patella. It is the largest joint in the

human body. The knee is a mobile trocho-ginglymus (a pivotal hinge joint), which

permits flexion and extension as well as a slight internal and external rotation. Although

the design of knee joint has not changed fundamentally over millennia, it is vulnerable to

both acute injury and the development of osteoarthritis. It is often grouped into

tibiofemoral and patellofemoral components.(The fibular collateral ligament is often

considered with tibiofemoral components.)When radiologist use x-ray to exam knee joint

the other organs receive effective dose are must be determined to protect patient from

radiation risks such as cancer.

 

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1.3. Objective: The main objective of this study, was measure dose received by organs in knee joint x-

ray examination.

1.3.1. Specific Objectives:

• To calculate the dose to body organs

• To compare the dose received by organs to standard level.

• To check the relationship between the dose received by organs and

Body Mass Index (BMI)

• To determine main dose for Pelvis x-rays examination.

 

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1.4. The anatomy of knee joint: The knee joint complex consists of the femur, the tibia, the fibula, and the patella(Figure

1-1). Distal end of the femur expands and forms the convex lateral and medial condyles,

which are designed to articulate with the tibia and the patella. The articular surface of the

medial condyle is longer from front to back than is the surface of the lateral condyle.

Anteriorly, the two condyles form a hollowed femoral groove, or trachea, to receive the

patella. The proximal end of the tibia,the tibial plateau, articulates with the condoyle of

the femur. On this flat tibia plateau are two shallow concavities that articulate with their

respective femoral condyles. The knee is one of the largest and most complex joints in

the body. The knee joins the thigh bone (femur) to the shin bone (tibia). The smaller bone

that runs along side the tibia (fibula) and the knee cap (patella) are the other bones that

make the knee joint. The patella is the largest sesamoid bone in the human body. It is

located in the tendon of the quadriceps femoris muscle and is divided into three medial

facets and a lateral facet that articulate with the femur (Figure 1-1). The lateral aspect of

the patella is wider than the medial aspect. The patella articulates between the concavity

provided by the femoral condyles. Tracking within this groove depends on the pull of the

quadriceps muscle and patellar tendon, the depth of the femoral condoles, and the shape

of the patella (Alindon et al, 1992).

 

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Figure 1-1. the bones of the knee joint; A; Anterior view B; Posterior view.

 

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Figure 1-2. articulations of Knee Joint

 

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Tendons connect the knee bones to the leg muscles that move the knee joint. The anterior

circulate ligament prevents the femur from sliding backward on the tibia(or the tibia

sliding forward on the femur). The posterior circulate ligament prevents the femur from

sliding forward on the tibia (or the tibia from sliding backward on the femur). The medial

and lateral collateral ligaments prevent the femur from sliding side to side. Two C-shaped

pieces of cartilage called the medial and lateral menisci act as shock absorbers between

the femur and tibia. Numerous bursar, or fluid filled sacs, help the knee move smoothly

figure (1-2) (Al-Zaharias and Bathetic, 2002)

Figure 1-2.

There are essentially four separate ligaments that stabilize the knee joint. On the sides of

the joint lie the medial collateral ligament (MCL) and the lateral collateral ligament

(LCL) which serve as stabilizers for the side-to-side stability of the joint. The MCL is a

broader ligament that is actually made up of two ligament structures, the deep and

superficial components, whereas the LCL is a distinct cord-like structure. In the front part

of the center of the joint is the anterior cruciate ligament(ACL). This ligament is a very

important stabilizer of the femur on the tibia and serves to prevent the tibia from rotating

and sliding forward during agility, jumping, and deceleration activities. Directly behind

the ACL is its opposite, the posterior circulate ligament (PCL)( Kendall et al, 2000). The

PCL prevents the tibia from sliding to the rear. The knee joint is a vulnerable joint that is

easily injured. This is due in part to the fact that the joint is well exposed and in the

middle of two long lever-arms, the femur and tibia. Unlike the hip joint which has a very

stable ball-and-socket configuration, the bone anatomy of the knee imparts little support

to the joint's stability. This makes the knee ligaments prone to injury with any contact to

the knee, or often with just the force of a hard muscle contraction (e.g.performing a quick

change of direction when sprinting). The menisci are two oval(semilunar) fibrocartilages

that deepen the articular facets of the tibia, cushion any stresses placed on the knee joint,

and maintain spacing between the femoralcondyles and tibial plateau. The consistency of

the menisci is much like that of the intervertebral disks. They are located medially and

laterally on the tibial plateau, orshelf. The menisci transmit one-half of the contact force

in the medial compartment and an even higher percentage of the contact load in the

 

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lateral compartment. The menisci help stabilize the knee, especially the medial

meniscus,when the knee is flexed at 90 degrees (Figure 1-3) (Alindon et al, 1992).

Figure 1-3. Tendons of Knee joint

 

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Figure 1-4. knee joint muscles

The medial meniscus is a C-shaped fibrocartilage, the circumference of which is attached

firmly to the medial articular facet of the tibia and to the joint capsule by the coronary

ligaments. Posterior, it is also attached to fibers of these membranous muscle. The lateral

meniscus is more O-shaped and is attached to the lateral articular facet on the superior

aspect of the tibia. The lateral meniscus also attaches loosely to the lateral articular

capsule and to the popliteal tendon. The ligament of Weisberg is the part of the lateral

meniscus that project upward, close to the attachment of the posterior cruciate ligament.

The transverse ligament joins the anterior Blood is supplied to each meniscus by the

medial vehicular artery. Each meniscus can be divided into three circumferential zones.

Red-red zone is the outer, or peripheral, one-third and has a good vascular supply; the

red-white zoneis the middle one-third and has minimal blood supply; and the white-white

zone,on the inner one-third, is a vascular Figure 1-4 (Oluwafisoye et al, 2009).

 

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1.5. Dose Measurement in Conventional x-ray: One of the typical human diagnostic techniques is x-ray. The x-ray examination depends

on the range of radiation given to the subject. The radiation from the x-ray depends

primarily upon the x-ray tube current (mA) tube voltage (kVp) and exposure time (s).

Assessment of radiation exposure during X-ray examination is of great importance in

range of radiation given to the subject. Pediatrics radiology should be governed with high

professional Techniques to minimize radiation hazard on children while they are

examined by X-ray parameters which are, involved in this project such as X-ray tube

voltage, X-ray tube current and the distance between the X-ray tube and patient's

skin(child). Different radiographic examinations representing different radiographic

techniques (tube voltage and current) were recorded reflecting the variety in the radiation

exposure value Computer Program was used to calculate the entrance skin exposure the

results show that the radiation exposure was still below the value of risk at this Time of

exposure ranging between (0.04-0.14) second. Arthritis is recognized as Major Public

health problem. Arthritis and related musculoskeletal disorders are frequently chronic,

disabling and painful. It is estimated that the total economic cost to the U.S. of

musculoskeletal conditions was over $65 billion in 1984.Indirect costs from lost earnings

and services represent a high proportion of these costs. These diseases represented the

second most common cause of co morbidity in the Framingham Stu. The ideal

mechanism for measuring the incidence and prevalence of these chronic conditions and

their impact is through a survey which includes a physical examination, radiographs,

laboratory tests and other procedures on a broad representative sample of the population.

Case Identification of the arthritis a Major concern to those interested in obtaining

complete and accurate figures. Many individuals do not know and therefore cannot report

what specific rheumatic disease, affects them. The American Rheumatism Association

definitions of a case are based on highly structured diagnostic criteria which, for

osteoarthritis and rheumatoid arthritis, require radiologic evidence. With the emphasis in

this survey on the health of the elderly, NHANES III provides particularly appropriate

context and population for the study of musculoskeletal conditions. The major diseases to

be identified are rheumatoid arthritis, osteoarthritis and gout. Cases will be defined by

 

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use of questions on characteristic symptoms of the various disease; a physician's

examination. Focusing on pain, tenderness, swelling and deformities of specified joints;

x-rays of the hands and wrists, and knees; and various serological analyses, including

rheumatoid factor and C-reactive protein. In addition to assessing the prevalence of the

rheumatic disease, it is important to measure the burden of the diseases on the daily life

of individuals. This information is necessary to establish health priorities and to monitor

the effectiveness of interventions in rheumatic disease. A series of questions that cover

mobility, physical activity and ability to care for oneself are included to determine the

extent of functional impairment (Andriacchi et al, 2002).

1.6. Effective dose: Radiation exposures to the human body, whether from external or internal sources,can

involve all or a portion of the body. The health effects of one unit of dose to the entire

body are more harmful than the same dose to only a portion of the body,e.g., the hand or

the foot. To enable radiation protection specialists to express partial body exposures (and

the accompanying doses) to portions of the body in terms of an equal dose to the whole

body, the concept of effective dose was developed. Effective dose, then, is the dose to the

whole body that carries with it the same risk as a higher dose to a portion of the body. As

an example, 8 rem (80mSv) to the lungs is roughly the same potential detriment as 1 rem

(10 mSv) to the whole body based on this idea table (1-1) (Astephen et al, 2008).

 

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Table 1-1. Shows the evolving tissue weighting factors

(1)

Where: E=effective dose, W=tissue weight factor, Dt=mean dose to tissue

 

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1.7. Measurement Of Dose in knee joint: PA and lateral knee x-rays for each x-ray, skin* dose is approximately ,12m Sv.Three x-

rays projections taken, one PA for both knees and one lateral for each knee. Full limb x-

ray. The effective dose equivalent was 4.5 milliSieverts reflecting the large area of

anatomy exposed even with appropriate shielding of gonads. Only skin dose is available

for the knee radiographs. Effective dose equivalent, not skin dose, is the appropriate

quantity for the assessment of the risk of radiation injury. The effective whole body

equivalent dose from the extremity radiographs is very small with proper beam coning

and shielding of gonads and visceral organs, as will be done in this study, and since onlya

small portion of the total body bone marrow is exposed. For example, exposure to the

testes or ovaries from a bilateral AP knee radiograph is less than 0.1 µSv (Astephen et al,

2008).

 

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1.8. The Radiographic technique of knee joint imaging: There are two general types of x-ray procedures either radiographic examination or

fluoroscopic examinations. Radiography is the use of ionizing electromagnetic radiation

such as X-rays to view objects. Although not technically radiographic techniques,

imaging modalities such as MRI are sometimes grouped in radiography because the

radiology department of hospitals handle all forms of imaging. Bony changes in

OA(Osteoarthritis) have traditionally been assessed using radiographs.In the early stages

of disease onset, developments such as osteophytes, subchondralsclerosis, or subchondral

cysts are well visualized with this modality. As OA progresses, radiography is used to

assess JSW(joint space area), which provides an indirect measureof the integrity of both

hyaline and fibrocartilage. OA(Osteoarthritis) severity is often classifiedby subsequent

JSN(joint space narrawing) and the simultaneous appearance of subchondral bone

abnormalities such as cysts or sclerosis. Since the 1970s, the standard view for

radiographic assessment of the tibiofemoral joint has been the extended-knee radiograph,

which is a bilateral antroposterior image acquired while the patient is weight-bearing,

with both knees in full extension. More recently, alternative imaging protocols have

proposed imaging of the flexed knee to address the shortcomings of the extended-knee

radiograph, which is suboptimal for longitudinal joint assessment. These protocols utilize

different degrees of knee flexion, X-ray beam angles, and positioning strategies, but all

create a contact point between the tibia and posterior aspect of the femoral condoyle for

improved visualization of the joint space (Hall, 2000). The primary utility of radiography

in the diagnosis of OA is for evaluation of JSW. JSW and subsequent JSN were

originally assessed using manual techniques that required minimal additional equipment

or processing software. However, these methods were time consuming and subjective and

have since been largely abandoned in favor of automated assessment, which provides

quick and precise measurements of JSW. In addition to improving reproducibility of semi

quantitative scoring or manual measurements, automated assessment has also sparked

additional characterizations of joint space, including minimum JSW, mean JSW, joint

space area, and location-specific JSW Several studies have shown minimum JSW to be

most reproducible and most sensitive to OA-related changes. Currently, the Kellgren-

 

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Lawrence (KL) grading scheme is the most widely used and accepted standard for

diagnosis of radiographic OA AKL grade of( 0) indicates that no radiographic features of

OA are present while a KL grade of (1) is defined as doubtful JSN and possible

osteophytic lipping.Radiographic OA receives a KL grade of denoting the presence of

definite osteophytes and possible JSN on antroposterior weight-bearing radiograph.

Further disease progression is graded as KL (3), characterized by multipleosteophytes,

definite JSN, sclerosis, possible bony deformity and KL grade which is defined by large

osteophytes, marked JSN, severe sclerosis and definitely bony deformity. The KL

grading scheme has been criticized for characterizing the progression of OA as a linear

process and combining osteophyte and JSN measurements. More recently, the

Osteoarthritis Research Society International atlas has developed OA classification scores

that evaluate tibiofemoral JSN and osteophytes separately in each compartment. While

radiography is useful for valuation of JSW, a 2008 study by Bellamy et al,

(2008).revealed that significant number of symptomatic patients show cartilage loss on

MRI even when JSN or disease progression is not visualized using radiography In this

study, Radiographic progression was 91% specific but only 23% sensitive for Cartilage

loss, Consequently, MRI is regarded as an important modality for bone imaging because

it can provide contrast that improves the assessment of subchondral bone integrity and

lesions figure 1-5.

 

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Figure 1-5. Antero-posterior weight bearing radiographs of a patient with

joint space

 

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narrowing and osteophyte formation consistent with bilateral medial osteoarthritis of the

knee.Joint pace narrowing is greater in the right knee (arrow) compare with the left knee.

B) A magnified view of the right knee joint. The arrow denotes medial JSN.Osteophyte

formation can be seen on the femur and tibia. An x-ray (radiograph) isa non-invasive

medical test that helps physicians diagnose and treat medical conditions. Imaging with x-

rays involves exposing a part of the body to a small dose of ionizing radiation to produce

pictures of the inside of the body. X-rays are the oldest and most frequently used form of

medical imaging. Good radiographic technique tends to produce a quality image while

reducing the examine dose. Ideally, the higher the voltage the lower will be the examinee

dose. This is so because of the inverse relationship between voltages and current

however, as voltages raised and the current lowered, the image contrast is reduced thus

possibly reducing the acceptability of the exposure. For example, mammography could

be done at far lower examinee doses if the operating voltage were increased. However,

the radiographic to produce a satisfactory x-ray, one must supply the x-ray tube with a

high voltage and a sufficient electric current. X-ray voltages are measured in kilovolts

peak (kVp). One kilovolt (kV) is equal to 1000 V of electric potential. X-ray currents are

measured in mille amperes (mA), where the ampere(A) is a measure of electric current.

Normal household current is a few amperes. The prefix kilo stands for (1000); the prefix

milli, for (1/1000), or (0.001). The voltage and the current create the power to drive the x-

ray tube to produce x-rays which then penetrate that part of the body to be examined, and

imprint the x-ray film. Contrast would be very poor and the image would contain less

Diagnostic information. In general, the highest practicable voltage with an appropriately

low current will be employed in all examinations. The speed of an image receptor can

greatly influence examinee dose. Newly developed rare earth. screens in conjunction with

matched photographic emulsions show relative speeds of up to twelve times of that for a

conventional calcium tungstate screen-film combination. Rare earth screen-film

combinations that will reduce examinee dose to one fourth will be used in the (NHANES

III) with no loss of diagnostic information. Higher examinee dose reductions are possible,

but the quality of the image would become performed some what by radiographic noise.

 

19  

Radiographs are the standard method for evaluating loosening or infection but are limited

in their sensitivity and specificity (Van Gelderen, 2004). Bone scans may be positive in

asymptomatic patients even 2 years postoperatively and are, therefore, most helpful when

evaluating patients many years after surgery. Joint aspiration is an effective method of

diagnosing infection after total knee arthroplasty if antibiotic treatment is withheld for at

least 2 weeks before. Repeat aspirations may be necessary. In questionable cases, the

combination of leukocyte and bone marrow imaging maybe helpful. CT and MRI appear

to be more sensitive than radiographs for granuloma detection and assessment. CT is

helpful for measuring component rotational alignment. Despite the development of newer

imaging techniques, the radiograph remains the most accessible tool in the evaluation of

the OA joint. The knee joint is typically evaluated using the extended-knee radiograph,

which is a bilateral antroposterior image acquired while the patient is weight-bearing,

with both knees in full extension More recently flexed knee radiographs with varying

degrees of flexion and X-ray beam angles have been employed to improve in articular

visualization. Radiographs are used to evaluate osteophyte formation and joint space

narrowing (JSN); grading schemes such as the Kellgren-Lawrence grading scheme and

the Osteoarthritis Research Society International classification score establish guidelines

for the diagnosis of OA progress (Berman et al, 2007)

.

1.9. 1.The Radiographic technique of knee joint imaging:

Methods: Pain is the major clinical symptom in osteoarthritis of the knee and a key determinant for

seeking medical care. Pain related to osteoarthritis of the knee not only contributes to

functional limitations and reduced quality of life but is also the leading cause of

impairment of mobility in the elderly population in the United States. Despite the

importance of pain in knee osteoarthritis, little is understood about its causes. The general

opinion is that only a modest association exists between radiographic features of

osteoarthritis and knee pain, particularly for mild radiographic osteoarthritis. Several

investigators have shown discordance between these two features of osteoarthritis: people

with clearly abnormal joint radiographs may have no or only mild pain whereas others

with pain may not have radiographic osteoarthritis, although this discordance is thought

 

20  

to be less with more severe stages of radiographic disease. Furthermore, although pain

has been associated with osteophytes on plain radiographs, it has generally not been

associated with joint space narrowing. Previous studies have shown a lack of high

concordance between pain symptoms and radiographic osteoarthritis, but such findings

should not be considered as evidence of a lack of causal association. The factor can be

strongly causally associated with an outcome, yet it may not be strong predictor of the

outcome on its own because several other factors may contribute to the outcome. This is

particularly relevant to the study of pain, which is a subjective experience and unique to

each person. Many factors, such as genetic predisposition, previous experience,

expectations about analgesic treatment,current mood, coping strategies (such as catastro

phasing), and sociocultural environment, contribute to a person’s response to pain. These

factors, which usually differ from person to person, are often neither measured nor

controlled for studies examining the relation of pain to radiographic osteoarthritis across

individual patients. Consequently, residual confounding may have diluted the association

bettween radiographic knee osteoarthritis and knee pain. The Radiographic Techniques

and Radiographic projection in Examination of knee join imaging depend on clinical

indication .It is important procedure that is easily.Reproducible a different Techniques are

possible figure( 1-5 (Demura et al, 2011)).

Figure 1-6. Position of patient for tunnel view of knee: the knee is flexed

40-50 degree with cassette under flexed knee the x-ray is angulated in

same degree from below to obtain view of inter condoyle notch.

 

21  

1.10. The estimate of skin dose for knee joint radiography: In diagnostic radiology there are fundamentally two reasons for measuring or estimating

radiation dose to patients firstly: measurement provides a means for setting and checking

standards of good practice as an aid to optimization of patient protection. Secondly:

estimate of techniques as properly justified and cases of accidental over exposure

thoroughly investigated .Both the optimization and justification of diagnostic medical

exposure are receiving increasing attention with the realization that clinical x-rays make

the major contribution from man-made source to collective population does in developed

countries and that there is considerable potential for reducing dose without detriment to

patient care.Diagnostic X-ray examinations play an important role in the health care of

the population. These examinations may involve significant irradiation of the patient and

probably represent the largest man-made source of radiation exposure for the population.

Radiation has been long known to be harmful to humans. The radiation exposure received

in X-ray examinations is known to increase the risk of malignancy as well as, above a

certain dose, the probability of skin damage and cataract. The biological effect of

radiation depends on the total energy of radiation absorbed (in joules) per unit mass (in

kg) of tissue or organ. This quantity is called absorbed dose and is expressed in Gray

(Gy). The radiation dose resulting from medical diagnostic procedures is the largest

contributor of the population dose because a large number of x-ray examinations are

conducted every year globally.

The patient dose resulting from an x-ray diagnostic procedure depends on:

• Number of parameters such as:

• Energy of the x-ray beam

• Beam current

• Exposure duration

• Type of image recording system (Mould, 2005)

If a patient is exposed to an X-ray beam, some X-ray photons will pass through the

patient without any interaction, and therefore will produce no biological effect. On the

other hand X-ray photons which are absorbed may produce effects. Absorbed dose of

 

22  

radiation can be measured and/or calculated and form basic evaluation of the probability

of radiation induced effects. In evaluating biological effects of radiation after a particular

exposure of the body, further factors such as the varying sensitivity of different tissues

and absorbed doses to different organs have to be taken into consideration. To compare

risks of partial and whole body irradiation in diagnostic radiology effective dose is

commonly used, and is expressed in severet(Sv). In today’s diagnostic radiology, there is

a growing concern about radiation exposure. This can be seen in the recommendations of

the International Commission on Radiation Protection (ICRP) and many other national

publications. All these recommendations advices that X-ray examinations should be

conducted using techniques that keep patients doses as low as compatible with the

medical purposes of the examinations. In order to achieve this recommendation, it is

necessary to understand the factors that affect the exposure and to be able to evaluate

patient’s doses. Intensive studies in the field of patient dose were conducted in the United

Kingdom (UK) (Dance, 2008). These studies eventually lead to the introduction of the

European Union Council Directive which made it compulsory that patients dose be

measured in every hospital and that doses should be compared to reference dose levels

established by the competent authorities. The need for standardization of radiation

exposure and guidance levels for various radiographic examinations has also been

proposed by the International Atomic Energy Agency (IAEA) as a safety standard. The

guidance levels by IAEA are based on UK and European studies (Wolbarst, 1993).

Several guidelines and dose reference levels were also published by number of

international organizations and was recently summarized by ICRP. These guidelines have

stimulated world wide interest in patients’ doses and several major dose surveys have

been conducted.Patient dose has often been described by the entrance skin dose (ESD) as

measured in the center of the X-ray beam. Because of the simplicity of its measurement,

ESD is considered widely as the index to be assessed and monitored. ESD is measured

directly using Thermo luminescence. Dosimeter (TLD) placed on the skin of the patient

or indirectly from the measurements of dose-area product using a large aTransmission

Ionization Chamber (TIC) placed between the patient and the X-ray tube. The use of TLD

method in ESD assessment is a time consuming process.TLD technique requires

prolonged annealing and reading process. Furthermore, the use of TLD technique

 

23  

requires special equipments and thorough calibration facilities which may not be

available in most X-ray departments. On the other hand TIC method does not provide

direct measurement of skin dose and mathematical equations are needed to convert TIC

reading into Skin dose. Because of the limitations associated with both TLD and TIC

transmission ionization chamber,several mathematical equations have been suggested to

relate skin dose to the, used exposure factors such as the applied:

• mAs

• Surface to skin distance (SSD),

• Filtration

• Field size

• Output

• The applied kVp.

(2)

These Equation provide an easy and more practical mean of estimating skin dose even

before exposure. They also provide the easiest and cheapest technique .That can be

employed in any kind of patient dose survey or audit. Despite the attractive nature of the

calculation methods of patient dose, one should make sure that the used Xray equipment

has an adequate QC protocol that ensures the accuracy of the measured exposure factors.

For the purpose of dose estimate, charts and monograms have been published (Frontera et

al, .2001).

 

24  

Figure 1-7. Ion chamber on dose product meter which is attached to

diaphragm housing.

 

25  

1.11. Entrance Surface Dose: The dose product area is most convententialy measured with specially design dose area

product meters.That consist of large parallel pate ionization chambers with suitable

electrometer the response of which in term of charge collected, is proportional both of

area of the chamber that is exposed to the primary x-ray beam and to the dose

(Hashimoto et al, 2003). When the chamber is setup pendicular and the center of x-ray

beam axis is a position where beam area will never of chamber its response is

proportional to product of beam area and the dose which is same in all planes normal to

the beam axis. These monograms and charts allow skin dose to be determined graphically

over the diagnostic range of kVp, source to skin distance SSD and filtration. The use of

those monograms and charts may be difficult and time consuming. An easier approach is

to develop a functional relation between skin dose and the radiographic parameters such

as kVp, mAs,SSD and filtration. Such an equation would make skin dose estimation

much easier and practical. Although ESD may be sufficient for quality control

measurements where the stability of the X-ray equipment is often of concern, the

entrance dose is not sufficient for comparison or evaluation of actual patient dose and

associated risk. If the risk involved in an X-ray examination is to be estimated, ESD is

not sufficient and patient dose needs to be described by other quantity that is more

directly related to radiation effect. At present, it is considered that radiation-induced

effect can be assessed by virtue of the radiation doses in different organs or tissues in the

body Such data (organ dose) cannot be measured directly in patients undergoing X-ray

examinations, and are difficult and time consuming to be obtained by experimental

measurements using physical phantoms. One way of estimating internal dose of a patient

is the percentage depth dose method. Percentage depth dose is defined as the ratio of the

absorbed dose at a certain depth to the dose at a reference depth (usually skin dose).

Percentage depth dose is usually measured using a water phantom and ionization

chamber. The dose is measured at the surface of the phantom and at various depths

Within the phantom.The percentage depth doses at various depths is then Calculated.

Patient’s organ dose is then calculated from the knowledge of The Organ depth and the

 

26  

previously calculated percentage depth. Provided That Sufficient information regarding

the exposure technique and patient Size Are Available, organ doses can be calculated to a

reasonable Approximation Using Monte Carlo simulation or depth-dose techniques.

 

27  

Chapter Two

Materials and Methods

2.1. Materials:

2.1.1.Equipments: In the present study, three different modalities X-ray machines, from Different

manufactures were used as described in Table 2.1:

X-rays Equipments Specifications Manufacturer

2.1.2. Patient: A total of 50 patients were examined in two radiology departments in Khartoum

Teaching Hospital. The data were collected using a sheet for all Patients in order to

maintain consistency of the information. The following Parameters were recorded age,

weight, height, body mass index (BMI) Derived from mass (kg)/ (height (m))and

exposure parameters were Recorded. The dose was measured for knee joint -rays

examination. The Examinations were collected according to the availability.

2.2. Methods 2.2.1.Study duration:

This study was performed in period of January to June 2014

2.2.2.Study place: This study conducted in Khartoum Teaching Hospital

 

28  

2.2.3.Method of data collection: This study involved patients undergoing knee joint radiographic examinations in the

Emergency department at Khartoum Teaching Hospital. The radiographic equipment

used was Toshiba imaging system. It has a Polydoros LX 50 Lite high frequency

generator with a general radiographic X-ray tube Optic 150/30/50HC.The target angle for

the X-ray tube was 12°, and the measured ripple for tube potential was in the region of

1%. Total filtration for the X-ray system was measured as 2.7 mm of aluminum

equivalent. A single exposure control system was available for use in the under-table or

vertical position. Preliminary work will establish that lateral knee joint examinations will

is carried out in two different ways depending on the clinical condition of the patient.

Patients with good mobility were lying on their side on the X-ray table with the X-ray

beam vertically above them. Immobile patients were lying supine on a trolley in front of a

vertical bucky with the X-ray beam horizontal. Both techniques used Exposure Control

and tube potential range between 85 kV and 100 kV depending on the patient

size.Average tube potential for both techniques will be in the region of 93 kV. With dose

audit, there were difficulties in complying with the requirement to collect dose data for

patients of a particular weight range (50–90 kg) within the busy environment of an

Emergency department. In this case, the decision took to increase the sample size to

approximately 50 patients and to exclude those of very large or small build but not

requiring the collection of patient weight information. Separate sets of DAP dose data

were collected for each of the two radiographic techniques.

Dose measurement: ESD which is defined as the absorbed dose to air at the center of the beam including back

scattered radiation, measured for all patients using mathematical equation in addition to

output factor and patient exposure factors. The exposure to the skin of the patient during

standard radiographic examination or fluoroscopy can be measured directly or estimated

by a calculation to exposure factors used and the Equipments specifications from formula

below:

 

29  

(3)

(OP) is the output in mGy/ (mA) of the X-ray tube at 80 kV at a focus distance of 1m

normalized to 10 mA s, (kV) the tube potential,( mA) the product of the tube current

(mA) and the exposure time(s), (FSD) the focus-to-skin distance (in cm).(BSF) the

backscatter factor, the normalization at 80 kV and 10 mAs was used as the potentials

across the X-ray tube and the tube current are highly stabilized at this point. BSF is

calculated automatically by the Dose Cal software after all input data are entered

manually in the software. The tube output, the patient anthropometrical data and the

radiographic parameters (kVp, mA s, FSD and filtration) are initially inserted in the

software. The kinds of examination and projection are selected afterwards.

2.2.4.Method of data analysis: The data was analyzed with SPSS program under windows with t-test to assess the

significance of data BMI and exposure factor. ICRP dose calculation program was used

to determine dose received by body organs.

2.2.5.Method of data storage: The data will store securely in password personal computer (PC)

2.2.6. Ethical issue:- Permission from radiology department was obtained.

 

30  

Chapter Three

The Results and Discussion

3.1 The Results This study involved 50 patients undergoing knee joint radiographic examinations in

radiology departments at Khartoum Teaching Hospital. The radiographic equipment used

was Toshiba and Shimadzu imaging system. It has a Polydoros LX 50 Lite high

frequency generator with a general radiographic X-ray tube Opti 150/30/50HC. The

target angle for the X-ray tube was 12°, and the measured ripple for tube potential was in

the region of 1%. Total filtration for the X-ray system measured as 2.7 mm of aluminum

equivalent. ESDs in this study were calculated using Dose Cal software. The software

was extensively used for patient dose measurements in diagnostic radiology and also

produced reliable results. For dose measurement using the software, the relation ship

between X-ray unit current time product (mAs) and the air kerma free in air was

established at reference point of 80 cm from tube focus for the range of tube potentials

encountered in clinical practice. The X-ray tube outputs, in mGy (mA s)21, were

measured using Unfors Xi dosemeter (Unfors Inc., Billdal, Sweden).This dosemeter was

calibrated by the manufacturer and reported to have accuracy 5%. ESD was calculated

using the Dose Cal software according to the equation previously mentioned. The results

were tabulated in the tables (mean ± standard deviation (sd)) and the range of the

readings in parenthesis (3-2,3-3,3-4). The dose values in diagnostic radiology are small,

therefore the dose were presented in milli-Gray.The mean and the standard deviation

were calculated using the excel software &SPSS program. For dose calculation, patient

individual exposure parameters distance (FSD),Patient demographic data (age, height,

weight, BMI) were presented per department. Patients’ ESD were measured in two

radiology departments equipped with three different imaging machines. The following

 

31  

routine types of X-ray examination of knee joint was adopted. The correlation coefficient

which is defined as a measure of the degree of linear relationship between two variables,

usually labeled X and Y used in this study to describe the relation between two variables

that affect patient dose ESD (mGy) against tube current time product(mAs)and tube

voltage (kV). Positive correlation coefficients were recorded (tube voltage (kV), tube

current and exposure time product (mAs) and Focus to skin distance, obtained between

these values. This means if the value of mAs or kV increases the value of the ESD

increases.For the group of patients where age distribution was measured, 19 % of patients

were within the 15-25 years age range, 21 % of patients were within the 26-35years age

range, 18 % of patients were within the 36-45 years age range, 22 % of patients were

within the 46-55 years age range, 20 % of patients were within the 56-65 years age range.

The key parameters for this group are shown in Table 3-1

Table 3-1 the age distribution for both gender among the study sample

For the group of patients where Body Mass Index (BMI) was measured, 19 % of patients

were within the 2.1 + .51 (male), 2.35 + 0.93 (female) BMI ratio range, 21% of patients

were within the 2.80 + 0.79 (male) , 2.97 + 0.92 (female) BMI ratio range, 18 % of

patients were within the 2.91 + 0.53 (male), 2.94 + 0.88 (female)BMI ratio range, 22 %

of patients were within the 3.1 + 0.43 (male) and 2.9 + 0.61(female) BMI ratio range, 20

 

32  

% of patients were within the 3.5 + 0.37 (male) and3.74 + 1.04 (female) BMI ratio range.

The key parameters for this group are shown in Table 3-2.

Table 3-2. the mean and standard deviation of Body mass index

Distribution for both gender among the study sample.

BMI(kg\m)

Figure 3-1: Correlation between entrance skin dose ESD (mGy) and

Weight (mass) of the body(kg) of patients undergoing knee joint X-ray.

 

33  

Where x-rays exposure factors (kVp and mAs) was measured, 19 % of Patients were

within the 51.0 + 3.1 (kVp), 28.6 + 5.3 (mAs)exposure factors Ratio range, 21 % of

patients were within the 53.1 + 6.2 (kVp) and29.6 + 6.4 (mAs) exposure factors ratio

range, 18 % of patients were within the58.1 + 7.7 (kVp) and 28.5 + 5.8 (mAs) exposure

factors ratio range, 22 % of Patients were within the 56.4 + 6.07 (kVp) and 29.8 + 5.8

(mAs) exposure Pactors ratio range, 20 % of patients were within the 57.31 + 7.3 (kVp)

and 27.7 + 6.1(mAs) exposure factors ratio range. The key parameters for this group are

shown inTable 3-3.

Table 3-3. the mean and standard deviation of exposure factors used for

knee joint examination in the study sample

 

34  

Figure 3-2: Correlation between entrance skin dose ESD (mGy) and tube

potential kVp to patients undergoing lateral knee joint X-ray.

Table 3.4: Exposure factors, number of films and dose values for knee

Joint examination Projection (

kVp m

A

Ti

me(sec

)

Fil

m

Dose(mGy)

(mean_+sd)

Antroposterior(AP)

5

7.40

28.

4

.21 1 2. 03_+.05

Lateral 6

57

28.

7

.21 1 4.13_+.05

 

35  

Figure 3-3: Correlation between entrance skin dose ESD (mGy) and the

product of the tube current (mAs) to patients undergoing knee joint X-ray.

 

36  

3.2 Discussion: Diagnostic X-ray examinations play an important role in the health care of the

population. These examinations may involve significant irradiation of the patient and

probably represent the largest man-made source of radiation exposure for the population.

Radiation has been long known to be harmful to humans. The radiation exposure received

in X-ray examinations is known to increase the risk of malignancy as well as, above a

certain dose, the probability of skin damage and cataract. Strategies for reduction of

patient doses without loss of diagnostic accuracy are therefore of great interest to society

and have been focused in general terms by the ICRP through the introduction of the

concept of diagnostic reference levels.. The main objective of aim study was to assess the

dose received by organ in knee joint radiographic examination. A total of 50 patients

were examined in two radiology department which equipped with different imaging

modalities in the Khartoum teaching hospital Tables 2-1 showed the details of x-rays

equipment specifications. For the group of patients where age distribution was measured,

% of patients were within the 15-25 years age range, 21 % of patients were within the 26

35 years age range, 18 % of patients were within the 36-45 years age range, 22 % of

patients were within the 46-55 years age range, 20 % of patients were within the 56-65

years age range. The key parameters for this group are shown in Table 3-1. For the group

of patients where Body Mass Index (BMI) was measured,19 % of patients were within

the 2.1 + .51 (male), 2.35 + 0.93 (female) BMI ratio range, 21 % of patients were within

the 2.80 + 0.79 (male) , 2.97 + 0.92 (female)BMI ratio range, 18 % of patients were

within the 2.91 + 0.53 (male), 2.94 + 0.88(female) BMI ratio range, 22 % of patients

were within the 3.1 + 0.43 (male) and2.9 + 0.61 (female) BMI ratio range, 20 % of

patients were within the 3.5 + 0.37(male) and 3.74 + 1.04 (female) BMI ratio range. The

key parameters for this group are shown in Table 3-2. For the group of patients where x-

rays exposure factors (kVp and mAs) was measured, 19 % of patients were within the

51.0 + 3.1(kVp), 28.6 + 5.3 (mAs) exposure factors ratio range, 21 % of patients were

with in the 53.1 + 6.2 (kVp) and 29.6 + 6.4 (mAs) exposure factors ratio range, 18 % of

patients were within the 58.1 + 7.7 (kVp) and 28.5 + 5.8 (mAs) exposure factors ratio

range, 22 % of patients were within the 56.4 + 6.07 (kVp) and 29.8 + 5.8(mAs) exposure

 

37  

factors ratio range, 20 % of patients were within the 57.31 + 7.3(kVp) and 27.7 + 6.1

(mAs) exposure factors ratio range. The key parameters for this group are shown in Table

3-3. Dose measurement during knee joint: examination have been reported by Gounares et al (2010) and Berman et al (2007)the

results of this study confirm the findings of the two reported studies, i.e. that conventional

radiology generally results in high ESDs in lateral projection rather than AP projection in

both conventional and computed radiology. The comparison between mean ESD (mGy)

in different examination and previous studies using conventional radiography. The dose

values for all examinations were below the previous reported studies except the study of

Oluwafisoye et al, (2009). This variation could be attributed to Exposure factors and

patient morphologic characteristics and the sensitivity Of the detectors. The limited

experience with digital technology and the Technologist may attempt to avoid noisy

images by using milliampere-Second settings higher than necessary for good image

quality. The effect of The kilovolt peak setting on the patient entrance dose at

conventional Radiology has been described by Al-Zaharni and Bakheit, (2005)

Whosuggested the use of higher kilovolt peak settings with additional Filtration and

alternative projection to study knee joint pathologies with low Dose and high contrast-

detail detect ability. In this study, it was found that Doses for knee joint for the entire

examination were lower than IAEA Guidelines. The Image quality met the criteria of the

departments for all Investigation. The Findings of this study are therefore no neither

completely unexpected nor in Contradiction with those of other trials. Therefore the

importance of dose Optimization during CR imaging must be considered.

 

38  

Chapter four

Conclusion ,Recommendations and References

4.1. Conclusion: This experimental study performed to measure of dose received by organs in knee joint x-

ray examination. In the emergency department, patients undergoing knee joit

radiography examination are positioned either lying on their side on an X-ray table with

the X-ray beam vertical or lying supine on a trolley with the X-ray examination have

been evident from various international dose surveys. Reference dose levels provide a

framework to reduce this variability and aid optimization of radiation protection. A total

of 50 patients were examined in two radiology departments in Khartoum teaching

hospital. The data were collected using a sheet for all patients in order to maintain

consistency of the information. The following parameters were recorded age, weight,

height, body mass index (BMI) derived from weight (kg)/ (height (m)) and exposure

parameters were recorded. The dose was measured for knee joint x-rays examination. The

examinations were Collected according to the availability. This study involved patients

Undergoing knee joint radiographic examinations in the emergency department at

Khartoum Teaching Hospital. The radiographic equipment Used Toshiba imaging

system. It has a Polydoros LX 50 Lite high frequency Generator with a general

radiographic X-ray tube Opti 150/30/50HC. The Target angle for the X-ray tube was 12°,

and the measured ripple for tube Potential will be in the region of 1%. Total filtration for

the X-ray system measured as 2.7 mm of aluminum equivalent. Finally, in this study, it

was Found that doses for knee joint for the entire examination were higher. The ESDs for

conventional radiology were lower in AP than those for lateral projection and LA

respectively. Unlike the previous studies, the dose in knee Joint radiography was higher

in conventional radiography compared to other Techniques. Recently digital and

computed radiography are becoming more popular due to the important advantage of

digital imaging is cost and access. The image quality met the criteria of the departments

 

39  

for all investigation. The findings of this study are therefore neither completely

unexpected nor in Contradiction with those of other trials. Therefore the importance of

dose Optimization during conventional radiology imaging must be considered.

 

40  

4.2. Recommendations:

• MRI is recommended for knee joint because of their ability to demonstrate the

soft tissue and muscle beside there no ionizing radiation exposure.

• Digital radiology is recommended for knee joint imaging because of Their high

image quality and avoidance the examination repetition.

• Advance training for medical staff is recommended for radiology staff To reduce

high dose to patient.

• Further studies are recommended with more number of patients and Using more

two modalities for comparison.

 

41  

4.3 References:-

1. Alindon, T. E., Snow, S., Cooper, C., & Dieppe, P. A.,1992, Patterns of

osteoarthritis of the knee joint in the community: The importance of The

patellofemoral joint. Annals of the Rheumatic Diseases, 51, P.p.844-849.Al-

Zaharni, K. S., Bakheit, A. M. 2002. A study of the Gait characteristics of patients

with chronic osteoarthritis of the knee. Disability and Rehabilitation, 24,275-280.

Doi:10.1080/09638280110087098Andriacchi, T., Galante, J., &Fermier, R. 2002,

The influence of total knee replacement design on Walking and stair-climbing.

2. Journal of Bone and Joint Surgery Mercian Volume, 64, 1328-1335.Astephen, J.

L., Deluzio, K. J., Caldwell, G. E., & Dunbar, M. J, 2008, Biomechanical changes

at the hip, knee, and ankle joints during Gait are associated with knee

osteoarthritis severity..

3. Journal Of Orthopedic Research, 26, 332-341.doi:10.1002/jor.20496

4. Bellamy, N., Buchanan, W. W., Goldsmith, C. H., Campbell, J., &Stilt, L.

W.,2008, Validation study of WOMAC: A health status instrument for measuring

clinically important patient relevant Outcomes to ant rheumatic drug therapy in

patients with osteoarthritis Of the hip or knee. Journal of Rheumatology, 15,

1833-1840.

5. Berman, A. T., Zarro, V. J., Boaco, S. J., & Israelite, C., 2007, Quantitative gait

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